This was the Warriors' sixth consecutive loss in all competitions as they remain stuck in seventh place, seven points behind Home United and Geylang International, who occupy fifth and sixth respectively.
The game began tepidly, with neither side threatening to break the deadlock.
However, a deflection in the 26th minute allowed Azwan Ali's shot to beat Warriors goalkeeper Yazid Yasin and give the hosts the lead.
Sergio managed to bury the rebound to cap a thoroughly deserved win for DPMM
Warriors had a good chance to equalise just three minutes later, but Wardun Yusof made a good save to tip away Shaiful Esah's powerful free-kick.
DPMM then came close in the 33rd minute, as Brian McLean's header at the far post went just wide.
Before the break, Shaiful threatened with another of his trademark free-kicks but his effort was inches away from goal.
Marijan Suto had a good chance to equalise for Warriors after the break but the Croatian contrived to head wide despite being unmarked in the 53rd minute.
The chances mostly came DPMM's way after that, with Yazid punching away a free-kick from Paulo Sergio on the hour mark before the striker hit the woodwork two minutes later.
The reigning champions finally doubled their lead in the 63rd minute, as Rafael Ramazotti met Azwan Ali's corner and flicked home.
Ramazotti was thwarted by Yazid in the dying embers of the game but his strike partner Sergio managed to bury the rebound to cap a thoroughly deserved win for DPMM.
Photo: Weixiang Lim/FFTcomments